What is PsExec ?

PsExec command line tool is part of the SysInternal Windows administration package that is widely used by IT administrators in Windows environments. PsExec enables admins to execute code on remote machines. The classic use case would be an employee that encounters an issue with his workstation and needs helpdesk assistance. 

Using PsExec the helpdesk person can connect to the employee’s machine and open a command line prompt as if he was working on the remote machine itself. In order to establish the connection, the remote user should have access privileges to the target machine and provide the name of the target machine, as well as his username and password in the following format:

PsExec -s \\MACHINE-NAME -u USERNAME -p PASSWORD COMMAND (the process to be executed following establishing the connection).

How is PsExec Used in Cyberattacks?

The seamless remote access PsExec enables from a source machine to a target machine is intensively abused by threat actors in the course of the lateral movement stage in cyberattacks. This would typically occur after the initial compromise of a patient-zero machine. 

From that point onward, attackers seek to expand their presence within the environment and reach either domain dominance or specific data they are after. PsExec provides them with a seamless and reliable way to achieve that for the following reasons. 

PsExec is now Incorporated into Ransomware Attacks

PsExec has been successfully used by threat actors for the past 15. However, several years ago it was mostly found in high-end cybercrime groups or elite APT units and was used in attacks that were focused on data theft. 

However, within the last five years, lateral the skill barrier has dropped significantly and lateral movement with PsExec is incorporated in more than 80% of ransomware attacks, making protection against malicious authentication via PsExec a necessity for every organization.

Why is it Hard to Protect Against Attacks that use PsExec for Lateral Movement?

PsExec is essentially a legitimate process, that can’t be blacklisted from the environment. This makes the distinction between the legitimate use of PsExec by admins and malicious one by threat actors an extremely difficult task for endpoint protection and SIEM products. 

There is practically no tool in the security stack that can provide efficient, real-time detection and prevention of malicious PsExec authentication. Learn how Silverfort solves this problem.

Frequently Asked Questions

  • What is PsExec used for?

    PsExec is a command-line tool that allows users to run programs on remote systems. It can be used to execute commands, scripts, and applications on remote systems, as well as to launch GUI-based applications on remote systems.

    PsExec uses the Microsoft Windows Service Control Manager (SCM) to start an instance of the service on the remote system, which allows the tool to run the specified command or application with the account’s privileges of the service account on the remote system.

    PsExec can be useful for a variety of tasks such as:

    • Remotely troubleshooting and diagnosing issues on systems
    • Running batch scripts and scheduled tasks on remote systems
    • Deploying software updates and patches to remote systems
    • Executing commands and scripts on multiple systems simultaneously

    However, it’s important to note that PsExec can be a powerful tool in the hands of attackers as well, since it allows them to execute arbitrary code on remote systems, potentially leading to privilege escalation and lateral movement in the network. Therefore, it is important to use PsExec securely and to limit the use of PsExec to trusted users and systems.

  • Is PsExec a PowerShell?

    PsExec is not a PowerShell. It is a command-line tool that allows users to run programs on remote systems.

    PowerShell, on the other hand, is a task automation and configuration management framework developed by Microsoft, which includes a command-line shell and associated scripting language built on the .NET framework. PowerShell can be used to automate various tasks and perform complex operations on local or remote systems.

    While both PsExec and PowerShell can be used to perform similar tasks, such as running commands on remote systems, they are different tools and have different capabilities. PsExec is designed to execute a single command or application on a remote system, while PowerShell is a more powerful framework that can be used to automate and manage various tasks, including running commands and scripts on remote systems.

    Therefore, depending on the scenario, one tool may be more appropriate than the other.

  • Is PsExec malware?

    PsExec is not malware itself, but it can be used by malware and attackers to perform malicious actions.

    PsExec is a legitimate tool that allows users to run programs on remote systems. It can be used for a variety of legitimate tasks such as troubleshooting, deploying software updates and patches, and executing commands and scripts on multiple systems simultaneously.

    However, PsExec can also be used by attackers to gain unauthorized access to remote systems and perform malicious actions. For example, an attacker could use PsExec to execute a malicious payload on a remote system, or to move laterally within a network and gain access to sensitive information.

    Therefore, it’s important to use PsExec securely and to limit the use of PsExec to trusted users and systems.